Should investors be worried about North Korea?

The opinions expressed in this commentary are solely those of Paul R. La Monica. Other than Time Warner, the parent of CNNMoney, Abbott Laboratories and AbbVie, La Monica does not own positions in any individual stocks.

North Korea is at again. Talk from Pyongyang about starting up a previously mothballed nuclear reactor is the latest bit of gamesmanship by North Korean leader Kim Jong Un.

So far, Wall Street is not worried about all the tension. The Dow and the S&P 500 both marched to new all-time highs Tuesday.

But it's a different story below the 38th parallel on the Korean peninsula. Even though stocks are in rally mode worldwide, South Korea's benchmark KOSPI Composite Index is down slightly year-to-date.

A top exchange-traded fund that tracks South Korean stocks, the iShares MSCI South Korea Capped Index Fund (EWY) has fared even worse. It's down nearly 8%. That ETF holds leading Korean companies, such as electronics giant Samsung, automaker Hyundai and steel firm POSCO. The Korea Fund (KF), a closed-end fund based in New York, has also been hit this year, losing about 6% of its net asset value.

One has to think that the saber rattling from Kim Jong Un is having some effect on investor sentiment in Seoul. After all, the South Korean economy is expected to grow at a reasonable, if not spectacular clip, this year. The Bank of Korea is also in easing mode. It cut interest rates twice last year. At last month's meeting, the central bank didn't rule out another cut at some point. Inflation is relatively low.

In other words, South Korea looks a lot like the United States. And the continuation of the low and slow barbecue recovery in the U.S. has been enough to keep Wall Street happy. The one big difference between South Korea and the United States? American investors don't have to seriously worry about someone up in Ottawa launching missiles across the border.

So I guess it probably makes sense for South Korea's market to be down a bit. In addition to the unique geopolitical risks, there are also questions about whether Japan's aggressive weakening of the yen will hurt the competitiveness of Korean tech and car companies on the global market.

During a conference call with investors last month, Sang Won Kim, lead portfolio manager of the Korea Fund at Allianz Global Investors U.S., said that the strengthening of Korea's won against the yen and the U.S. dollar is a significant concern.

Still, the big question for the rest of the world is whether or not the North Korea nuclear concerns are enough to lead to a pullback on Wall Street. Will North Korea be the catalyst to take down a stock market that may sorely need a correction?

That seems doubtful. Even though North Korea reportedly has a list of U.S. targets it could hit in a military strike, many experts think Kim Jong Un is bluffing.

The fact that Austin, Texas, made the list led to some amusing social media chatter last week, giving rise to a #whyaustin meme on Twitter. Does Kim Jong Un have a gripe with well-known companies based in or near the Lone Star State's capital? Maybe he has a Dell (DELL) computer that always crashes? Does he, like most of the free world, think that prices at Whole Foods (WFM) are too high? Or perhaps Kim Jong Un really really doesn't like Matthew McConaughey and Sandra Bullock?

"How much does North Korea threaten international security? It's minimal," said Jeffrey Sica, president and chief investment officer of SICA Wealth Management in Morristown, N.J. "Of course, you have to watch Kim Jong Un. But there are other much bigger global concerns."

In a blog post last week, analysts from advisory firm Asia-Pacific Global Research wrote that while Kim Jong Un is likely just posturing for now, "a certain amount of attention must be focused on a possible 'black swan' event in which a small foreseen or unforeseen event can trigger retaliation by the other side."

That's scary. The budget cuts in the U.S. are probably priced into stocks. Ditto for more economic turmoil in Cyrpus and the rest of Europe. But an actual resumption of the Korean War? I don't think that's something Wall Street is baking into this increasingly frothy market.

Of course, investors probably don't need to be obsessively worried about North Korea. But they shouldn't ignore it either.

"This market has been oblivious to bad news this year. But North Korea would be something the Fed can't fix. It is the kind of bolt out of the blue risk that you can't plan for," said Scott Armiger, chief investment officer of Christiana Trust.

Paul R. La Monica is an assistant managing editor at CNNMoney. He is the author of the site's daily column, The Buzz, and also tweets throughout the day about the markets and economy @LaMonicaBuzz. La Monica also oversees the site's economic, markets and technology coverage.